Posts Tagged ‘Alzheimer’s disease’

Young carriers of the APOE4 allele have brains that are more connected (left, red lines illustrate connections between brain areas) and active (right, yellow indicates activity) than the brains of those without the allele.
KRISHNA SINGH, ELIFE, 8:E36011, 2019.

A growing body of evidence supports the theory that neural hyperactivity and hyperconnectivity precede the pathological changes that lead to neurodegeneration.

DIANA KWON

There are approximately 5.6 million people over the age of 65 living with Alzheimer’s disease in the United States. With the population aging, that number is projected to grow to 7.1 million by 2025. Researchers know that age, a family history of the disease, and carrying a genetic variant known as APOE4 are all associated with a higher chance of developing the condition. But the biological mechanisms leading to Alzheimer’s are still largely a mystery.

Over the last decade, scientists have amassed evidence for a hypothesis that, prior to developing full-blown Alzheimer’s disease, patients experience a period of hyperactivity and hyperconnectivity in the brain. Several functional magnetic resonance imaging studies have reported that people with mild cognitive impairment (MCI), a condition that often precedes Alzheimer’s, appear to have higher brain activity levels than their age-matched counterparts. Researchers have also found signs of such changes in healthy people carrying the APOE4 allele, as well as in presymptomatic stages of Alzheimer’s in rodent models of the disease.

Krishna Singh, a physicist and imaging neuroscientist at the Cardiff University Brain Research Imaging Center (CUBRIC) in the UK, and his colleagues wanted to investigate this theory further. Previous studies of brain activity in young APOE4 carriers were mostly conducted using small sample sizes, according to Singh. But by the mid-2010s, his team had access to neuroimaging data from close to 200 participants studied at CUBRIC as part of an effort to build a massive dataset of healthy brains. So the researchers decided to use the data to search for signs of unusual brain activity and connectivity in people with the APOE4 allele.

Using magnetoencephalography (MEG), a neuroimaging technique that records the magnetic fields generated by electrical activity in the brain, Singh and his colleagues had measured resting-state brain activity in a group of 183 healthy adults, which included 51 individuals who carried at least one copy of APOE4. The average age of the participants was 24 years old, although ages ranged from 18 to 65 years old.

Analysis of the imaging data revealed that, compared with controls, young APOE4 carriers displayed greater activity in several regions in the right side of the brain, including parts of what’s known as the default mode network, which is active when a person is not focused on a specific task. A similar set of brain regions also showed an overall increase in connectivity.

The researchers next compared the results to brain activity and connectivity data from a previous neuro­imaging study they had conducted, which found that elderly people with early-stage Alzheimer’s disease had decreased neuronal activity and connectivity compared with that of age-matched controls. The network of brain areas that displayed increased connectivity in young APOE4 carriers, the team found, partially overlapped with the brain regions that exhibited a decrease in connectivity in people with early-stage Alzheimer’s. These findings are intriguing, Singh says, because they suggest that brain areas that end up getting impaired in Alzheimer’s may be highly active and connected early in life—long before symptoms of the disease appear.

“This study adds further evidence that hyperactivity and hyperconnectivity may play an influential role in Alzheimer’s disease,” says Tal Nuriel, a professor of pathology and cell biology at the Columbia University Medical Center who wasn’t involved in the work. Because this was an observational study, the findings can only establish a correlation between brain activity and Alzheimer’s, Nuriel adds, so it’s still unclear whether the hyperactivity and hyperconnectivity observed during the early stages of the disease are a cause or a consequence of pathological changes that lead to neurodegeneration.

Scientists used to think that increased activity was simply a compensatory effect—the brain trying to make up for a loss of neurons and synapses, says Willem de Haan, a neurologist at the Amsterdam University Medical Center who was not involved in the latest study. “But I think there’s overwhelming evidence that this may actually be pathological hyperactivity.”

Much of that evidence comes from animal experiments conducted over the last decade or so. In rodents, researchers have found that hyperactivity can increase the production and spread of amyloid-ß, the peptide that accumulates into plaques found in the brains of people with Alzheimer’s—and that amyloid-ß can in turn induce neuronal hyperactivity. These findings have led some scientists to speculate that there might be a self-amplifying loop, where a progressive hyperactivity and build-up of amyloid-ß drives pathological changes associated with the neurodegenerative disease.

Research in humans also supports the idea that hyperactivity could play a causal role in Alzheimer’s disease. In 2012, researchers at Johns Hopkins University treated individuals with MCI with the anti-epileptic drug levetiracetam and found that the therapy suppressed activity in the hippocampus and led to improved memory performance. The team is currently testing levetiracetam for MCI in clinical trials. “I think this is one of the most interesting results,” says de Haan. “It seems to show that by correcting hyperactivity we can actually find some improvements in patients that might point to a completely new type of therapy for [Alzheimer’s disease].”

For the current study, Singh’s team also trained a machine-learning algorithm to distinguish APOE4 carriers from non-carriers based on their MEG data and tested whether it would be able to predict cases of Alzheimer’s. They found that while the program was able to perform above chance, the effect was not significant. “In a way, that was kind of encouraging,” Singh says. “Because I don’t think anybody would predict that we could find a signature [for Alzheimer’s] in 20- and 30-year-olds.”

For now, Singh says, his team’s findings simply shed light on what might be going on in the brains of people with the APOE4 allele. There are still a number of unanswered questions—such as when the transition from hyper- to hypoconnectivity and activity happens, what changes occur in the largely understudied middle-aged cohort, and whether there are differences between APOE4 carriers who go on to develop Alzheimer’s and those who don’t. Ultimately, to understand how disruptions in neuronal activity lead to behavioral and cognitive deficits, scientists need to decipher what’s going on inside a healthy brain, Singh says. “[We] require a model of how the brain works—and those are still in their infancy.”

https://www.the-scientist.com/notebook/genetic-risk-for-alzheimers-disease-linked-to-highly-active-brains-66483?utm_campaign=TS_DAILY%20NEWSLETTER_2019&utm_source=hs_email&utm_medium=email&utm_content=78081371&_hsenc=p2ANqtz-98aZf5axxCqtPYITNqfIVWKM6xuk3ni-QSpgTS4gFXzeQcntecrOf6DFFXjrf5qcktWTUz2M3xnAEJlvXTaS7WDQEKNg&_hsmi=78081371

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A technology that originated at the University of Minnesota is well on its way to commercialization thanks to an investment award from Alzheimer’s Drug Discovery Foundation (ADDF).

The investment of up to $500,000 was awarded through the ADDF’s Diagnostics Accelerator initiative. Toronto, Ontario-based RetiSpec licensed through the University of Minnesota’s Technology Commercialization program. The technology harnesses hyperspectral imaging and machine learning.

“We are focused on bringing to market a noninvasive, easy-to-use, screening technology that can change when and how we detect Alzheimer’s disease at its earliest stages including before a patient presents with symptoms,” said Eliav Shaked, CEO of RetiSpec. “Early detection provides an important window of opportunity for timely therapeutic interventions that can slow or even prevent the progression of Alzheimer’s disease. ADDF’s investment represents another point of external validation of the promise of our technology.”

In preclinical studies and a pilot human study, the retinal imaging technology was effective in detecting small changes in biomarkers associated with elevated cerebral amyloid beta levels early in the disease process including before the onset of clinical symptoms.

RetiSpec is currently collaborating with Toronto Memory Program, Canada’s largest Alzheimer’s clinical trial site, to validate the accuracy and usability of the technology in patients.

“We believe that RetiSpec’s retinal scanner stands out and shows promise as a unique diagnostic tool among a range of technologies in development,” said Howard Fillit , MD, founding executive director and chief science officer of ADDF The technology has the potential to facilitate early diagnosis, improve the lives of patients and their loved ones and save the healthcare system money and resources. The technology will also be useful in making clinical trials for Alzheimer’s disease more efficient.”

https://www.mddionline.com/feast-your-eyes-new-technology-early-alzheimers-screening

Many people with Alzheimer’s disease take the drug donepezil (brand name Aricept) to help ease symptoms for a time. But those on the drug should be aware of a rare but potentially life-threatening side effect. The drug can cause muscles to break down, leading to a condition called rhabdomyolysis that can lead to kidney damage and even death.

The risk of hospitalization for rhabdomyolysis was more than double that for those taking Aricept compared to other Alzheimer’s drugs, a new study reports.

Still, the condition is very rare, and anyone taking Aricept should not stop taking it. But because rhabdomyolysis is potentially very serious, patients should be aware of the problem and seek medical care should symptoms arise.

The main symptom of rhabdomyolysis, or rhabdo as it is commonly called, is intense muscle pain or weakness that does not go away. Urine can also turn dark. Emergency treatment is needed to manage the condition and may require a week or longer stay in the hospital.

For the study, Canadian researchers analyzed data on 220,353 men and women over age 65 who had gotten a prescription between 2002 and 2017 for one of three Alzheimer’s drugs: donepezil, rivastigmine (Execlon) or galantamine (Razadyne).

There were 88 hospitalizations for rhabdo among 152,300 patients taking donepezil (0.06 percent prevalence), compared to 16 cases among the 68,053 patients taking one of the other drugs (0.02 percent prevalence).

The authors note that doctors should rule out rhabdo if someone on an Alzheimer’s drug comes to the hospital because of constant muscle pain. Still, the condition remains very rare (about 25,000 per year in the U.S. from all causes), and most of the cases in the current study were not life-threatening.

Other medications may also trigger the condition, including antipsychotic medications, which are also often prescribed to people with Alzheimer’s disease to allay symptoms like agitation and aggression. Cholesterol-lowering statin drugs have also been tied to an increased risk of rhabdo. It is possible that Aricept cannot trigger rhabdo alone. Further studies will be required to determine what other cofactors might act with Aricept to trigger rhabdo.

The condition more commonly arises after intense physical exertion, often in people who have not been training regularly. The condition can arise in military recruits undergoing basic training, and in people beginning high-intensity workouts at the gym.

By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.

Jamie L. Fleet, Eric McArthur, Aakil Patel, et al: “Risk of rhabdomyolysis with donepezil compared with rivastigmine or galantamine: a population-based cohort study.” CMAJ – Canadian Medical Association Journal, Sept. 16, 2019


Brain tissue from deceased patients with Alzheimer’s has more tau protein buildup (brown spots) and fewer neurons (red spots) as compared to healthy brain tissue.

By Yasemin Saplakoglu

Alzheimer’s disease might be attacking the brain cells responsible for keeping people awake, resulting in daytime napping, according to a new study.

Excessive daytime napping might thus be considered an early symptom of Alzheimer’s disease, according to a statement from the University of California, San Francisco (UCSF).

Some previous studies suggested that such sleepiness in patients with Alzheimer’s results directly from poor nighttime sleep due to the disease, while others have suggested that sleep problems might cause the disease to progress. The new study suggests a more direct biological pathway between Alzheimer’s disease and daytime sleepiness.

In the current study, researchers studied the brains of 13 people who’d had Alzheimer’s and died, as well as the brains from seven people who had not had the disease. The researchers specifically examined three parts of the brain that are involved in keeping us awake: the locus coeruleus, the lateral hypothalamic area and the tuberomammillary nucleus. These three parts of the brain work together in a network to keep us awake during the day.

The researchers compared the number of neurons, or brain cells, in these regions in the healthy and diseased brains. They also measured the level of a telltale sign of Alzheimer’s: tau proteins. These proteins build up in the brains of patients with Alzheimer’s and are thought to slowly destroy brain cells and the connections between them.

The brains from patients who had Alzheimer’s in this study had significant levels of tau tangles in these three brain regions, compared to the brains from people without the disease. What’s more, in these three brain regions, people with Alzheimer’s had lost up to 75% of their neurons.

“It’s remarkable because it’s not just a single brain nucleus that’s degenerating, but the whole wakefulness-promoting network,” lead author Jun Oh, a research associate at UCSF, said in the statement. “This means that the brain has no way to compensate, because all of these functionally related cell types are being destroyed at the same time.”

The researchers also compared the brains from people with Alzheimer’s with tissue samples from seven people who had two other forms of dementia caused by the accumulation of tau: progressive supranuclear palsy and corticobasal disease. Results showed that despite the buildup of tau, these brains did not show damage to the neurons that promote wakefulness.

“It seems that the wakefulness-promoting network is particularly vulnerable in Alzheimer’s disease,” Oh said in the statement. “Understanding why this is the case is something we need to follow up in future research.”

Though amyloid proteins, and the plaques that they form, have been the major target in several clinical trials of potential Alzheimer’s treatments, increasing evidence suggests that tau proteins play a more direct role in promoting symptoms of the disease, according to the statement.

The new findings suggest that “we need to be much more focused on understanding the early stages of tau accumulation in these brain areas in our ongoing search for Alzheimer’s treatments,” senior author Dr. Lea Grinberg, an associate professor of neurology and pathology at the UCSF Memory and Aging Center, said in the statement.

The findings were published Monday (Aug. 12) in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.

https://www.livescience.com/alzheimers-attacks-wakefulness-neurons.html?utm_source=notification

In a pilot study of 14 older adults with mild cognitive problems suggestive of early Alzheimer’s disease, Johns Hopkins Medicine researchers report that a high-fat, low-carbohydrate diet may improve brain function and memory.

Although the researchers say that finding participants willing to undertake restrictive diets for the three-month study—or partners willing to help them stick to those diets—was challenging, those who adhered to a modified Atkins diet (very low carbohydrates and extra fat) had small but measurable improvements on standardized tests of memory compared with those on a low-fat diet.

The short-term results, published in the April issue of the Journal of Alzheimer’s Disease, are far from proof that the modified Atkins diet has the potential to stave off progression from mild cognitive impairment to Alzheimer’s disease or other dementias. However, they are promising enough, the researchers say, to warrant larger, longer-term studies of dietary impact on brain function.

“Our early findings suggest that perhaps we don’t need to cut carbs as strictly as we initially tried. We may eventually see the same beneficial effects by adding a ketone supplement that would make the diet easier to follow,” says Jason Brandt, Ph.D., professor of psychiatry and behavioral sciences and neurology at the Johns Hopkins University School of Medicine. “Most of all, if we can confirm these preliminary findings, using dietary changes to mitigate cognitive loss in early-stage dementia would be a real game-changer. It’s something that 400-plus experimental drugs haven’t been able to do in clinical trials.”

Brandt explains that, typically, the brain uses the sugar glucose—a product of carbohydrate breakdown—as a primary fuel. However, research has shown that in the early stage of Alzheimer’s disease the brain isn’t able to efficiently use glucose as an energy source. Some experts, he says, even refer to Alzheimer’s as “type 3 diabetes.”

Using brain scans that show energy use, researchers have also found that ketones—chemicals formed during the breakdown of dietary fat—can be used as an alternative energy source in the brains of healthy people and those with mild cognitive impairment. For example, when a person is on a ketogenic diet, consisting of lots of fat and very few sugars and starches, the brain and body use ketones as an energy source instead of carbs.

For the current study, the researchers wanted to see if people with mild cognitive impairment, often an indicator of developing Alzheimer’s disease, would benefit from a diet that forced the brain to use ketones instead of carbohydrates for fuel.

After 2 1/2 years of recruitment efforts, the researchers were able to enroll 27 people in the 12-week diet study. There were a few dropouts, and so far, 14 participants have completed the study. The participants were an average age of 71. Half were women, and all but one were white.

To enroll, each participant required a study partner (typically a spouse) who was responsible for ensuring that the participant followed one of two diets for the full 12 weeks. Nine participants followed a modified Atkins diet meant to restrict carbs to 20 grams per day or less, with no restriction on calories. The typical American consumes between 200 and 300 grams of carbs a day. The other five participants followed a National Institute of Aging diet, similar to the Mediterranean diet, that doesn’t restrict carbohydrates, but favors fruits, vegetables, low- or fat-free dairy, whole grains and lean proteins such as seafood or chicken.

The participants and their partners were also asked to keep food diaries. Prior to starting the diets, those assigned to the modified Atkins diet were consuming about 158 grams of carbs per day. By week six of the diet, they had cut back to an average of 38.5 grams of carbs per day and continued dropping at nine weeks, but still short of the 20-gram target, before rising to an average of 53 grams of carbs by week 12. Participants on the National Institute of Aging diet continued to eat well over 100 grams of carbs per day.

Each participant also gave urine samples at the start of the dietary regimens and every three weeks up to the end of the study, which were used to track ketone levels. More than half of the participants on the modified Atkins diet had at least some ketones in their urine by six weeks into the diet until the end; as expected, none of the participants on the National Institute of Aging control diet had any detectable ketones.

Participants completed the Montreal Cognitive Assessment, the Mini-Mental State Examination and the Clinical Dementia Rating Scale at the start of the study. They were tested with a brief collection of neuropsychological memory tests before starting their diets and at six weeks and 12 weeks on the diet. At the six-week mark, the researchers found a significant improvement on memory tests, which coincided with the highest levels of ketones and lowest carb intakes.

When comparing the results of tests of delayed recall—the ability to recollect something they were told or shown a few minutes earlier—those who stuck to the modified Atkins diet improved by a couple of points on average (about 15% of the total score), whereas those who didn’t follow the diet on average dropped a couple of points.

The researchers say the biggest hurdle for researchers was finding people willing to make drastic changes to their eating habits and partners willing to enforce the diets. The increase in carbohydrate intake later in the study period, they said, suggests that the diet becomes unpalatable over long periods.

“Many people would rather take a pill that causes them all kinds of nasty side effects than change their diet,” says Brandt. “Older people often say that eating the foods they love is one of the few pleasures they still enjoy in life, and they aren’t willing to give that up.”

But, because Brandt’s team observed promising results even in those lax with the diet, they believe that a milder version of the high-fat/low-carb diet, perhaps in conjunction with ketone supplement drinks, is worth further study. As this study also depended on caregivers/partners to do most of the work preparing and implementing the diet, the group also wants to see if participants with less severe mild cognitive impairment can make their own dietary choices and be more apt to stick to a ketogenic diet.

A standardized modified Atkins diet was created and tested at Johns Hopkins Medicine in 2002, initially to treat some seizure disorders. It’s still used very successfully for this purpose.

According to the Alzheimer’s Association, about 5.8 million Americans have Alzheimer’s disease, and by 2050 the number is projected to increase to 14 million people.

Jason Brandt et al. Preliminary Report on the Feasibility and Efficacy of the Modified Atkins Diet for Treatment of Mild Cognitive Impairment and Early Alzheimer’s Disease, Journal of Alzheimer’s Disease (2019). DOI: 10.3233/JAD-180995

https://medicalxpress.com/news/2019-06-low-carb-keto-diet-atkins-style-modestly.html

Doctors have newly outlined a type of dementia that could be more common than Alzheimer’s among the oldest adults, according to a report published Tuesday in the journal Brain.

The disease, called LATE, may often mirror the symptoms of Alzheimer’s disease, though it affects the brain differently and develops more slowly than Alzheimer’s. Doctors say the two are frequently found together, and in those cases may lead to a steeper cognitive decline than either by itself.

In developing its report, the international team of authors is hoping to spur research — and, perhaps one day, treatments — for a disease that tends to affect people over 80 and “has an expanding but under-recognized impact on public health,” according to the paper.

“We’re really overhauling the concept of what dementia is,” said lead author Dr. Peter Nelson, director of neuropathology at the University of Kentucky Medical Center.

Still, the disease itself didn’t come out of the blue. The evidence has been building for years, including reports of patients who didn’t quite fit the mold for known types of dementia such as Alzheimer’s.

“There isn’t going to be one single disease that is causing all forms of dementia,” said Sandra Weintraub, a professor of psychiatry, behavioral sciences and neurology at Northwestern University Feinberg School of Medicine. She was not involved in the new paper.

Weintraub said researchers have been well aware of the “heterogeneity of dementia,” but figuring out precisely why each type can look so different has been a challenge. Why do some people lose memory first, while others lose language or have personality changes? Why do some develop dementia earlier in life, while others develop it later?

Experts say this heterogeneity has complicated dementia research, including Alzheimer’s, because it hasn’t always been clear what the root cause was — and thus, if doctors were treating the right thing.

What is it?

The acronym LATE stands for limbic-predominant age-related TDP-43 encephalopathy. The full name refers to the area in the brain most likely to be affected, as well as the protein at the center of it all.

“These age-related dementia diseases are frequently associated with proteinaceous glop,” Nelson said. “But different proteins can contribute to the glop.”

In Alzheimer’s, you’ll find one set of glops. In Lewy body dementia, another glop.

And in LATE, the glop is a protein called TDP-43. Doctors aren’t sure why the protein is found in a modified, misfolded form in a disease like LATE.

“TDP-43 likes certain parts of the brain that the Alzheimer’s pathology is less enamored of,” explained Weintraub, who is also a member of Northwestern’s Mesulam Center for Cognitive Neurology and Alzheimer’s Disease.

“This is an area that’s going to be really huge in the future. What are the individual vulnerabilities that cause the proteins to go to particular regions of the brain?” she said. “It’s not just what the protein abnormality is, but where it is.”

More than a decade ago, doctors first linked the TDP protein to amyotrophic lateral sclerosis, otherwise known as ALS or Lou Gehrig’s disease. It was also linked to another type of dementia, called frontotemporal lobar degeneration.

LATE “is a disease that’s 100 times more common than either of those, and nobody knows about it,” said Nelson.

The new paper estimates, based on autopsy studies, that between 20 and 50% of people over 80 will have brain changes associated with LATE. And that prevalence increases with age.

Experts say nailing down these numbers — as well as finding better ways to detect and research the disease — is what they hope comes out of consensus statements like the new paper, which gives scientists a common language to discuss it, according to Nelson.

“People have, in their own separate bailiwicks, found different parts of the elephant,” he said. “But this is the first place where everybody gets together and says, ‘This is the whole elephant.’ ”

What this could mean for Alzheimer’s

The new guidelines could have an impact on Alzheimer’s research, as well. For one, experts say some high-profile drug trials may have suffered as a result of some patients having unidentified LATE — and thus not responding to treatment.

In fact, Nelson’s colleagues recently saw that firsthand: a patient, now deceased, who was part of an Alzheimer’s drug trial but developed dementia anyway.

“So, the clinical trial was a failure for Alzheimer’s disease,” Nelson said, “but it turns out he didn’t have Alzheimer’s disease. He had LATE.”

Nina Silverberg, director of the Alzheimer’s Disease Research Centers Program at the National Institute on Aging, said she suspects examples like this are not the majority — in part because people in clinical trials tend to be on the younger end of the spectrum.

“I’m sure it plays some part, but maybe not as much as one might think at first,” said Silverberg, who co-chaired the working group that led to the new paper.

Advances in testing had already shown that some patients in these trials lacked “the telltale signs of Alzheimer’s,” she said.

In some cases, perhaps it was LATE — “and it’s certainly possible that there are other, as yet undiscovered, pathologies that people may have,” she added.

“We could go back and screen all the people that had failed their Alzheimer’s disease therapies,” Nelson said. “But what we really need to do is go forward and try to get these people out of the Alzheimer’s clinical trials — and instead get them into their own clinical trials.”

Silverberg describes the new paper as “a roadmap” for research that could change as we come to discover more about the disease. And researchers can’t do it without a large, diverse group of patients, she added.

“It’s probably going to take years and research participants to help us understand all of that,” she said.

https://www.cnn.com/2019/04/30/health/dementia-late-alzheimers-study/index.html

by Carly Cassella

Over a dozen dolphins, stranded on the beaches of Florida and Massachusetts, have been found with brains full of amyloid plaques, a hallmark of Alzheimer’s disease. The scientists who made the discovery think it may be a warning to us all: alongside the Alzheimer’s-like plaques, the team also found the environmental toxin BMAA.

Produced by blue-green algae blooms, this neurotoxin is easily caught up in the ocean food web, and chronic dietary exposure has long been suspected to be a cause of neurological disease, including Alzheimers, Parkinson’s and Amyotrophic Lateral Sclerosis (ALS).

The presence of both BMAA and amyloid plaques in 13 stranded dolphins now adds even more weight to this hypothesis.

“Dolphins are an excellent sentinel species for toxic exposures in the marine environment,” says neurologist Deborah Mash from the University of Miami.

“With increasing frequency and duration of cyanobacterial blooms in coastal waters, dolphins might provide early warning of toxic exposures that could impact human health.”

They might also be a good animal model for how BMAA could trigger Alzheimer’s disease. In 2017, it was discovered that dolphins are the only known wild animal to show signs of this common human disease.

Meanwhile, dolphins that inhabit Florida coastal waters are also commonly exposed to recurring harmful algae blooms (HABs). This might just be a coincidence, but experiments have shown that chronic BMAA dietary exposure can trigger neurodegenerative changes in both humans and non-human primates.

“Acute and chronic exposures to such toxins can be harmful to both humans and animals resulting in respiratory illnesses, severe dermatitis, mucosal damage, cancer, organ failure and death,” the authors write.

As the world warms at a rapid rate, these HABs are only becoming more frequent, and the authors worry that dolphins will accumulate even more BMAA as a result, “both by exposure to HABs and by the ingestion of prey previously exposed to the cyanotoxin”.

As such, these creatures may very well be our first indication of poor environmental conditions, and while it’s still not clear if these blooms directly lead to Alzheimer’s in dolphins or in humans, the researchers say it’s a risk we shouldn’t be willing to take.

“The $64,000 question is whether these marine mammals experienced cognitive deficits and disorientation that led to their beaching,” says co-author Paul Alan Cox, an ethnobotanist at the Brain Chemistry Labs in Jackson Hole.

“Until further research clarifies this question, people should take simple steps to avoid cyanobacterial exposure.”

This study has been published in PLOS ONE.

https://www.sciencealert.com/beached-dolphins-had-alzheimer-s-like-plaques-and-it-s-a-warning-to-us-all